Drawing tubes.



Patented Feb. II, I902.

S. E. DIESCHER.

DRAWING TUBES. (Application filed Jan. 10, 1801.) (No Modal.) 4 Sheets$heet l.

WESSESI Emmi? No. 693,1!9. Patented Feb. ll, I902. S. E. DIESCHEB.

DRAWING TUBES.

(Applicatiop filed Jan. 10, 1901.)

4 $heets$heet 2.-

(No Model.)

fa asses:

Z-WM-MW %W% No. 693,|I9. Patented Feb. 11, I902. s. E. DIESCHER.

DRAWING TUBES.

(Applichtion filed Jam 10, 1901.)

(No Model.) 4 Shaw s-Sheet 4.

WITNESSES: v INVENTOR I Atty.

UNITED STATES .PATENT OFFICE.

SAMUEL E. DIESOHER, OF PITTSBURG, PENNSYLVANIA.

DRAWING TUBES.

SPECIFICATION forming part of Letters Patent No. 693,119, dated February 11, 1902. Application filed January 10,1901. Serial No. 42,773. (Nomodel-l To all whom it may concern.-

Be it known that I, SAMUEL E. DIESCHER, a citizen of the United States, residing at Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented or discovered certain new and useful Improvements in Drawing Tubes, of which improvements the following is a specification.

The invention described herein relates to certain improvements in the manufacture of tubes, and has for its object the production of tubes having smooth and hardened or compacted inner and outer surfaces.

In general terms the invention consists in subjecting a highly-heated tube to successive drafts or reductions by drawing-dies simultaneously operative on successive portions of the tubes, the reduction or draft in each one being preferably proportioned to or approximately to the strength of the tube at the point or plane where each die operates; and the invention further consists in effecting a compacting and smoothing of the inner wall of the tube by subjecting it to the rubbing and reducing action of surfaces operative simul-' taneous with and in the same planes as the dies.

The invention is hereinafter more fully described and claimed.

In the accompanying drawings, forming a part of this specification, Figure 1 is a View, partly in plan and partly in section, of a machine for drawing tubes. Fig. 2 is a side elevation of the machine. Figs. 3 and 4 are sectional views of the dies and mandrel, the sections being in planes atright angles to each other. Fig. 5 shows the mandrel inside and end elevation. Fig. 6 shows the mandrel in longitudinal and transverse section. Fig. 7 is a similar view, the plane of section being at right angles to that of Fig. 6; and Fig.8 is a diagrammatic View illustrating the action of the dies and mandrel on the tube.

In the practice of my invention I employ any suitable form or construction of draft; mechanism for pulling the pipe through the dies-as, for example, that shown in Figs. 1 and 2, consisting of jaws 1 for gripping the bar or tag 2, which is secured to the end of the pipe. The jaws are mounted on abuggy 3, and a hook 4, adapted to be shifted into and out of engagement with the draft-chain 5, is

so connected to the gripping-jaws that the latter are closed by a pull on the hook. The dies 6, 7, and 8 are secured in any suitable manner to the front of the machine, preferably in holding-blocks 9, which are firmly bolted to the abutment 10 on the machine, as clearly shown in Figs. 1, 2, 3, and 4:. The rear end of the mandrel is secured in a sliding block 11, mounted in a suitable guide and holding frame 12 in front of the draft mechanism. The block 11 is shifted in the frame to move the mandrel into and out of the dies and to adjust it into proper relation to the dies by any suitable mechanism, as the screw 13, which will serve not only to shift and adjust the mandrel, but also to hold itin position when adjusted.

The mandrel is constructed with the successive portions, against which the pipe or tube is forced by the dies, progressively smaller, so that the tube is in contact with the mandrel only in the planes of reduction. This feature of construction may be carried out in various ways; but it is preferred to form the mandrel in three or more tubular sections 14: 15 16, &c., corresponding to the number of dies employed. The sections are held together by means of a rod 17, passing through the sections, and provided at one end with a head and screwing at the opposite end into the holding or supporting bar 18. The lengths of the mandrel-sections are dependent upon the spacing of the dies-that is to say, the lengths of the sections should not exceed and are preferably a little less than thedistances between the operative surfaces of the dies. When the machine is in operation, the mandrel-sections are so adjusted that the rear ends of the operative or bearing surfaces of the sections are in planes passing through the operative surfaces of the dies, so that the tube will bear upon or be in frictional contact with the mandrel for as short distances as possible. I

As in some cases it is desirable to apply a lubricant or other material to the interior wall of the tube, the mandrel-holder 18 is made tubular, and the tie-rod 17 has an axial opening 19, from which extends branch openings 20, the latter extending through the mandrel-sections, preferably, at points at or near the front ends of said sections, as clearly ICO shown in Fig. 6, as the tube is notin contact with the sections at their front ends, as shown in Fig. 8. The lubricant-such as plumbago, soapstone, &c.is forced through the holder, tie-rod, and branch openings by compressed air or gas or othersuitable means. Provision is made for the escape of air by radial openings 21, arranged at an angle to the openings 20 and extending into longitudinal passages 22, formed by grooving the tie-rod or inner walls of the mandrel-sections, or both. These passages extend to the rear end of the mandrel, asshown in Fig. 7.

The dies 6, 7, and 8 are preferably made in the form of disks and are held within recesses in the blocks 9. The blocks are made with openings larger than the pipe or tube to be drawn, and provision is made by passages 23 through the blocks for the introduction of a lubricant or other material to the spaces in the blocks around the pipe or tube, as shown in Fig. 4. r

In drawing a tube one end thereof is secured to a tag or pull-rod, such attachment being preferably done by closing the walls of the tube down onto a conical head 2 on the end of the rod, as shown in Figs. 3, 4, and 8. This construction forms a more certain and durable connection between the tube and draft mechanism than Where tongs are used or the tag welded to a portion of the pipe. The tube is suitably heated and placed in position in front of the first die, the pull-rod being passed through the dies and connected to the draft mechanism. The mandrel is then pushed into the tube until its end bears against the end of the pull-rod. The draft mechanism is then started, pulling the rod through the first die 6. By the action of this die the tube is forced down onto the section 14 of the mandrel, which will at this time move forward with the tube. The pull exerted on the tube will effect a stretching of the same and pull a short portion off the end of the section 14. As the pipe and mandrel move forward through the die 7 there will be a further reduction of the external diameter of the pipe, a further stretching thereof, and consequent stripping of a portion of the tube from the section 14. The elongation efiected in the die 7, as indicated at b in Fig. 8, is greater than before,being the resultant of the stretching and the reduction in the thickness of its walls. As soon as the front end of the section 1 1 of the mandrel has passed slightly beyond the smallest diameter of the opening through the die 8 the movement'of the mandrel is checked, and thereafter the tube is caused to slip along the mandrel. As before stated, the mandrel-sections are so proportioned as to length that when the front end of the section 15 has been adjusted to proper relation to die 8 the front ends of sections 15 and 16 will have approximately the same relation to the dies 7 and 6t'. a, will be slightly in front of the smallest diameter of the die-openings.

The draft or amount of reduction effected by each of the several dies is controlled largely by the COHditlOTl-t. e., the temperature and tensile strength-of the portions of the pipe or tube at and in the rear of the planes of action of the dies. As, for example,the tube or pipe is highly heated when subjected to the action of the die 6 and also after passing through said die, and hence, although the metal of the tube is in a condition favorable to a heavy draft or reduction, the tensile strength of the portion of the tube in the rear of the die 6 is comparatively small, the regulation of the draft or reduction must be regulated to some extent in accordance with tensile strength of the tube in the rear of the die. As the portions of the tube in the rear of the dies 7 and 8 are subjected not only to the strain necessary to pull it through said dies, but also to the strain required to pull it through preceding dies, the draft or reduction effected in any one die is regulated to some extent in accordance with the tensile strength of the tube in the rear of each die and also in the rearof each succeeding die of the series. As the tube is subjected also to the strain necessary to strip it from each section of the mandrel, such. strain must also be considered in proportioning the draft or reduction of each die.

It will be readily understood by those skilled in the art thatin passing through the dies and over the mandrel both the inner and outer walls of the tube are subjected to an active working and that after being subjected to the stretch incident to its being pulled through all the dies except the last of the series the stretched metal is again-compressed or worked by the succeeding die. As the tube after passing through the last die is comparatively cold, its tensile strength is higher, and relatively little stretching will occur in the rear of the last die. It is preferred that the draft or reductions should be so proportioned and the rate of movement of the tube so regulated that it will be comparatively cold and subjected to slight stretching after passing through the last die in order to avoidany material change in the dimensions imparted to the tube by the last die and last sect-ion of the mandrel.

I claim herein as my invention 1. In a machine for drawing tubes, the combination of a series of two or more dies, a mandrel passing through the dies, means for holding the mandrel stationary and means for pulling a tube through the dies and along the mandrel, whereby the tube is subjected to transverse red uction and longitudinal tension while being operated on, substantially as set forth.

2. In a machine for drawing tubes the combination of a series of two or more dies, a mandrel extending through the dies, means for holding the mandrel stationary relative to the dies and means for applying a tensional strain to the tubes while being acted on by the dies and mandrel, substantially as set forth.

3. In a machine for drawing tubes, the combination of a series of two or more dies, a mandrel extending through the dies, said mandrel having progressively smaller reducing or operative portions, means for holding the mandrel stationary relative to the dies and means for applying a tensional strain to the tube While being acted on by the dies and mandrel, substantially as set forth.

4:. In a machine for drawing tubes the combination of a series of two or more dies, a sectional mandrel, each section being of less diameter than the preceding section, means for holding the mandrel stationary relative to the dies and means for applying a tensional SAMUEL E. DIESCHER.

Witnesses: DARWIN S. WOLCOTT, F. E. GAITHER. 

